Fuel cell vehicle
An exhaust gas exhausted from a fuel cell is sent to a silencer through an exhaust pipe. The silencer is provided with a conductive noise absorbing material, and is fixed to a vehicle body through a metallic fixing jig. Thus, the noise absorbing material is earthed to the vehicle body so that it is possible to prevent static electricity from being generated in the use of the fuel cell vehicle such as in a low humidity environment.
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The present invention claims foreign priority to Japanese patent application no. 2004-347749, filed on Nov. 30, 2004, the subject matter of which is incorporated herein by reference.
BACKGROUND OF THE INVENTION1. Field of the Invention
The present invention relates to a fuel cell vehicle provided with a silencer for reducing an exhaust noise exhausted from a fuel cell.
2. Description of the Related Art
As a fuel cell used for a fuel cell vehicle, a PEM (Proton Exchange Membrane) fuel cell which employs solid polymer as an electrolyte membrane is commonly adopted. In this kind of fuel cell vehicle, power generation is carried out by the electrochemical reaction between air and hydrogen within the fuel cell. The air not used for the power generation is externally exhausted through an exhaust pipe together with water created by the electrochemical reaction. Further, since the fuel cell is supplied with high pressure air, the high pressure exhaust gas flows through the exhaust pipe. Therefore, the exhaust pipe is provided with a silencer for reducing a noise (see Japanese Patent Unexamined Publication JP-A-2003-291657 for example).
However, since a thin electrolyte membrane partitions an anode electrode (hydrogen electrode) and a cathode electrode (oxygen electrode) as for the solid polymer electrolyte fuel cell, the hydrogen supplied to the anode electrode permeates the cathode electrode via electrolyte membrane. As a result, the exhaust gas may contain a minute amount of hydrogen. For such a portion which may contain hydrogen, there has been a demand for solving a problem of a static electricity being generated in a condition such as dry environment.
SUMMARY OF THE INVENTIONIn view of above problem, one of objects of the present invention is to provide a fuel cell vehicle that removes, by a simple configuration, the static electricity which may be generated, particularly in an exhaust pipe of a fuel cell vehicle.
According to a first aspect of the present invention, there is provided a fuel cell vehicle including a vehicle body, a fuel cell for generating an electric power through electrochemical reaction between a fuel gas and an oxidizer gas, an exhaust pipe for exhausting an exhaust gas exhausted from the fuel cell, a silencer for absorbing an exhaust noise due to the exhaust gas, and a conductive noise absorbing material provided within the silencer. The conductive noise absorbing material is earthed to the vehicle body.
Therefore, the static electricity which may be generated in the exhaust pipe can be dissipated to the vehicle body.
According to a second aspect of the present invention, as set forth in the first aspect of the present invention, it is preferable that the silencer include a silencer body, and a noise absorbing pipe. The noise absorbing pipe is communicated with the exhaust pipe and housed within in the silencer body. The noise absorbing pipe is provided with the conductive noise absorbing material on the periphery thereof, the conductive noise absorbing material being earthed to the vehicle body via the silencer body.
According to a third aspect of the present invention, as set forth in the second aspect of the present invention, it is preferable that the noise absorbing pipe have a plurality of through-holes on a pipe wall thereof.
In such a configuration, not only the static electricity generated in the exhaust pipe can be dissipated to the vehicle body but also the exhaust noise due to the exhaust gas can be absorbed effectively and quickly.
According to a fourth aspect of the present invention, as set forth in the second aspect of the present invention, it is preferable that the silencer body include a pair of end walls, at least one of the end walls being provided with the noise absorbing material so that the noise absorbing effect can be further enhanced.
According to a fifth aspect of the present invention, as set forth in the third aspect of the present invention, it is preferable that the pipe wall be provided with a pair of slits, a portion of the pipe wall placed between the pair of slits being outwardly bent into a curved shape so as to serve the pair of slits as the through-hole. In such a configuration, since the exhaust gas smoothly flows along the curved surface of the portion placed between the pair of slits outwardly from the noise absorbing pipe. Therefore, the noise absorbing effect when the noise being absorbed by the noise absorbing material can be further enhanced.
According to a sixth aspect of the present invention, as set forth in the fourth aspect of the present invention, it is preferable that silencer further include a first separator arranged parallel to the end walls within the silencer body, a second separator arranged parallel to the end walls within the silencer body, a first muffling chamber formed between one of the end wall and the first separator, a second muffling chamber formed between the first separator and the second separator, and a third muffling chamber formed between the second separator and the other end wall.
According to a seventh aspect of the present invention, as set forth in the first aspect of the present invention, it is preferable that the noise absorbing material include stainless steel.
According to an eighth aspect of the present invention, as set forth in the first aspect of the present invention, it is preferable that the noise absorbing material include carbon.
According to a ninth aspect of the present invention, as set forth in the first aspect of the present invention, it is preferable that the silencer and the vehicle body be fixed by a conductive fixing jig.
According to a tenth aspect of the present invention, there is provided a silencer for a fuel cell vehicle including a silencer body, and a noise absorbing pipe. The noise absorbing pipe is communicated with the exhaust pipe of a fuel cell and housed within in the silencer body. The noise absorbing pipe is provided with the conductive noise absorbing material on the periphery thereof, the conductive noise absorbing material being earthed to a vehicle body via a silencer body.
According to an eleventh aspect of the present invention, as set forth in the tenth aspect of the present invention, it is preferable that the noise absorbing pipe have a plurality of through-holes on a pipe wall thereof.
According to a twelfth aspect of the present invention, as set forth in the tenth aspect of the present invention, it is preferable that the silencer body include a cylindrical shell having a pair of end walls, at least one of the end walls being provided with the noise absorbing material so that the noise absorbing effect can be further enhanced.
According to a thirteenth aspect of the present invention, as set forth in the eleventh aspect of the present invention, it is preferable that the pipe wall be provided with a pair of slits, a portion of the pipe wall placed between the pair of slits being outwardly bent into a curved shape so as to serve the pair of slits as the through-hole. In such a configuration, since the exhaust gas smoothly flows along the curved surface of the portion placed between the pair of slits outwardly from the noise absorbing pipe. Therefore, the noise absorbing effect when the noise being absorbed by the noise absorbing material can be further enhanced.
According to a fourteenth aspect of the present invention, as set forth in the fourth aspect of the present invention, it is preferable that silencer further include a first separator arranged parallel to the end walls within the silencer body, a second separator arranged parallel to the end walls within the silencer body, a first muffling chamber formed between one of the end wall and the first separator, a second muffling chamber formed between the first separator and the second separator, and a third muffling chamber formed between the second separator and the other end wall.
According to a fifteenth aspect of the present invention, as set forth in the tenth aspect of the present invention, it is preferable that the noise absorbing material include stainless steel.
According to a sixteenth aspect of the present invention, as set forth in the tenth aspect of the present invention, it is preferable that the noise absorbing material include carbon.
According to a seventeenth aspect of the present invention, as set forth in the tenth aspect of the present invention, it is preferable that the silencer and the vehicle body be fixed by a conductive fixing jig.
In accordance with the above described aspects of the present invention, the exhaust noise of the exhaust gas can be reduced in a simple configuration. In addition, since the silencer is provided with the conductive noise absorbing material in a state of conductive noise absorbing material being earthed to the vehicle body, the static electricity which may be generated in the exhaust pipe can be dissipated to the vehicle body, thereby preventing the static electricity from accumulating in the exhaust pipe.
As seen from
The fuel cell FC is provided in an underfloor region at the midsection of the fuel cell vehicle V, being housed in a fuel cell system box B which is fixed to the side members M1, M2 at the bottom thereof. The fuel cell system box B houses not only the fuel cell FC but also a diluter 10 (see
The hydrogen supplying system 5 includes a hydrogen tank 5a equipped with an electromagnetically operated cut-off valve (not shown) and filled with highly purified hydrogen at high pressure, a pressure reducing valve 5b for reducing the pressure of the hydrogen supplied from the hydrogen tank 5a, an ejector 5c for recycling circulated hydrogen, a purge valve 5d. Incidentally, the hydrogen tank 5a is fixed onto a frame (not shown), the frame being fixed at the lower side of the vehicle body M.
The air supplying system 6 includes a compressor 6a for compressing air taken in from outside the vehicle and supplying the compressed air to the fuel cell FC, an inter cooler (not shown) for cooling the compressed air supplied from the compressor 6a, a humidifier (not shown) for humidifying the compressed air cooled by the inter cooler.
As seen from
In the retention region 13, the hydrogen exhausted from the fuel cell FC flows through the anode-gas off pipe 3b at the time of purge processing. The purge processing is carried out intermittently by opening the purge valve 5d on the anode-off gas pipe 3b. In the dilution region 14, the air exhausted from the fuel cell FC flows through the cathode-off gas pipe 4b. The hydrogen in the retention region 13 moves into the dilution region 14 through the holes 12a and is diluted by being mixed with the air in the dilution region 14. Incidentally, the purge processing is a hydrogen releasing process carried out in order to prevent the output power from being lowered owing to the impurities. Such impurities can be nitrogen contained in the air moved from the cathode electrode 4 to the anode electrode 3 through the electrolyte membrane 2 and/or the water created by the reaction.
The exhaust pipe 20 is formed and is extended from the fuel cell system box B toward the rear section of the fuel cell vehicle V (vehicle body M), as shown in
As seen from
Further, the silencer 30 is provided with an exhaust flow-in pipe (noise absorbing pipe) 22 communicating with the exhaust pipe 20 (see
The exhaust flow-in pipe 22 penetrates through the end wall 33, the first separator 35 and the second separator 36 so as to communicate with the third muffling chamber R3. The exhaust flow-in pipe 22 has a number of transmitting-holes 22a formed in on a pipe wall 22b in an area where passes through the second muffling chamber R2.
The inner pipe 23 penetrates through the first separator 35 and the second separator 36 so as to communicate the first muffling chamber R1 with the third muffling chamber R3. The inner pipe 23 has a number of transmitting-holes 23a formed in an area where passes through the second muffling chamber R2. The inner pipe 23 communicates with the exhaust flow-in pipe 22 and the second muffling chamber R2 through the transmitting-holes 23a.
The exhaust flow-out pipe 24 penetrates through the first separator 35, second separator 36, and end wall 34 so as to communicate the first muffling chamber R1 with the outside of the vehicle.
In such a configuration as described above, there are two flowing paths of the exhaust gas flowed in the exhaust flow-in pipe 22. One path reaches the exhaust flow-out pipe 24 via third muffling chamber R3, inner pipe 23 and the first muffling chamber R1, whereas another path reaches the exhaust flow-out pipe 24 via transmitting-holes 22a, second muffling chamber R2, transmitting-holes 23a, inner pipe 23 and the first muffling chamber R1.
The end wall 33 has a plate member 33a and a plate member 33b facing each other, and between which a fourth muffling chamber R4 is formed. The plate member 33a has a plurality of transmitting-holes 33a1 formed on the portion corresponding to the fourth muffling chamber R4 (see
In the silencer 30 according to this embodiment, the electrically conductive noise absorbing materials 45, 46, 47 are provided in the second muffling chamber R2, fourth muffling chamber R4 and fifth muffling chamber R5. These noise absorbing materials 45, 46, 47 can be selected from stainless wool made from stainless steel fiber, carbon-series fiber, conductive fiber, etc. The conductive fiber is a synthetic fiber such as nylon and polyester of which the surface is coated with conductive filler such as carbon black, or of which the interior is filled with conductive filler. Incidentally, a plurality of electrically conductive noise absorbing materials may be mixed. Further, the outer periphery of the exhaust flow-out pipe 24 may be previously wrapped by the electrically conductive noise absorbing material having a predetermined thickness.
Additionally, as seen from
Further, as seen from
Next, referring to
The exhaust gas from the exhaust pipe 20, as seen from
By designing the fuel cell vehicle so that the exhaust gas passes through the silencer 30, the noise in a wide range of frequency can be reduced by the first to fifth muffling chambers R1 to R5. Further, the noise at a specific frequency can be reduced by resonance through the transmitting-holes 22a, 23a. The noise due to friction can be also reduced by the noise absorbing materials 45 to 47.
Meanwhile, when the fuel cell vehicle V is used in a low humidity environment such as a cold district or a cold period of time, static electricity is likely to be generated. However, in this embodiment, the electrically conductive noise absorbing materials 45 to 47 are provided within the silencer 30. The noise absorbing materials 45 to 47 are kept in contact with the shell 32 of the silencer 30, and the silencer 30 is earthed to the vehicle body M through the electrically conductive jig 42. In accordance with such a configuration, it is possible to prevent static electricity from being generated or accumulated in the exhaust pipe 20 and silencer 30.
As seen from
By providing the pair of slits 22c, the exhaust gas introduced into the exhaust flow-in pipe 22A from the exhaust pipe 20 flows out from the transmitting-holes formed at the slits 22c as indicated by arrows in
In addition, in the case of the silencer 30 according to this embodiment being employed for the fuel cell vehicle V, the temperature of the fuel cell FC is kept at about 80° C. while driving. Therefore, the noise absorbing material such as carbon can be adopted, which have not been adopted to a silencer of the vehicle having an internal combustion engine because of its low heat resistance.
Incidentally, the pairs of slits 22c can be applied to not only the exhaust flow-in pipe 22, but to both the exhaust flow-in pipe 22 and the inner pipe 23, to only the inner pipe 23 or to the plate members 33a, 34a of the end walls 33, 34. Further, the arrangement of the exhaust flow-in pipe 22, inner pipe 23 and the exhaust flow out pipe 24 should not be limited to that in the embodiment described-above. The exhaust-flow-out pipe 24 may be arranged at the center whereas the flow-in pipe 22 and inner pipe 23 may be arranged on both sides thereof.
While there has been described in connection with the preferred embodiments of the present invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the present invention. It is aimed, therefore, to cover in the appended claims all such changes and modifications as fall within the true spirit and scope of the present invention.
Claims
1. A fuel cell vehicle comprising:
- a vehicle body;
- a fuel cell for generating an electric power through an electrochemical reaction between a fuel gas and an oxidizer gas;
- an exhaust pipe for exhausting an exhaust gas exhausted from the fuel cell; and
- a silencer in communication with the exhaust pipe for reducing an exhaust noise due to the exhaust gas, the silencer and the vehicle body are fixed by a conductive fixing jig, wherein the silencer comprises: a silencer body; an inner pipe provided within the silencer body; a noise absorbing pipe in communication with the exhaust pipe and housed within the silencer body, wherein the inner pipe and the noise absorbing pipe create first and second flowing paths of exhaust gas inside the silencer body; and a noise absorbing material provided within the silencer body,
- wherein the noise absorbing material is a conductive material grounded to the vehicle body,
- wherein the silencer body comprises a cylindrical shell having a pair of end walls provided at both openings thereof, each of said pair of end walls has a dual-plate structure,
- wherein a first portion of the noise absorbing material is provided between the dual plates of each of said pair of end walls, and
- wherein a plurality of transmitting holes is formed through a portion of said at least one of the pair of end walls facing the inner pipe.
2. The fuel cell vehicle according to claim 1, wherein the noise absorbing pipe is provided with a second portion of said noise absorbing material on a periphery thereof, and
- the noise absorbing material is grounded to the vehicle body via the silencer body.
3. The fuel cell vehicle according to claim 1, wherein the noise absorbing pipe has a plurality of through-holes on a pipe wall thereof.
4. The fuel cell vehicle according to claim 3, wherein the pipe wall is provided with a pair of slits, and
- a portion of the pipe wall placed between the pair of slits is outwardly bent into a curved shape so as to serve the pair of slits as the through-hole.
5. The fuel cell vehicle according to claim 1, wherein the silencer further comprises:
- a first separator arranged parallel to the end walls within the silencer body;
- a second separator arranged parallel to the end walls within the silencer body;
- a first muffling chamber formed between one of the end walls and the first separator;
- a second muffling chamber formed between the first separator and the second separator wherein a second portion of the noise absorbing material is provided inside the second muffling chamber; and
- a third muffling chamber formed between the second separator and the other end wall.
6. The fuel cell vehicle according to claim 5,
- wherein the fuel cell vehicle further comprises a tailpipe extending to an outside of the fuel cell vehicle,
- wherein the silencer further comprises an exhaust flow-out pipe in communication with tailpipe, and
- wherein the exhaust gas flows along the first flowing path by passing through the noise absorbing pipe, the third muffling chamber, the inner pipe, the first muffling chamber and the exhaust flow-out pipe.
7. The fuel cell vehicle according to claim 5,
- wherein the fuel cell vehicle further comprises a tailpipe extending to an outside of the fuel cell vehicle,
- wherein the silencer further comprises an exhaust flow-out pipe in communication with tailpipe, and
- wherein the noise absorbing pipe has a plurality of through-holes formed on a wall thereof;
- wherein the inner pipe has a plurality of through-holes formed on a wall thereof; and
- wherein the exhaust gas flows along the second flowing path by passing through the noise absorbing pipe, the plurality of through-holes of the noise absorbing pipe, the second muffling chamber, the plurality of through-holes of the inner pipe, the inner pipe, the first muffling chamber and the exhaust flow-out pipe.
8. The fuel cell vehicle according to claim 1, wherein the noise absorbing material includes stainless steel.
9. The fuel cell vehicle according to claim 1, wherein the noise absorbing material includes carbon.
10. The fuel cell vehicle according to claim 7, wherein the exhaust gas also flows along the first flowing path by passing through the noise absorbing pipe, the third muffling chamber, the inner pipe, the first muffling chamber and the exhaust flow-out pipe.
11. The fuel cell vehicle according to claim 1, wherein the noise absorbing material includes at least one of nylon and polyester.
12. The fuel cell vehicle according to claim 1, wherein the plurality of transmitting holes faces the noise absorbing pipe.
13. A silencer for a fuel cell vehicle comprising:
- a silencer body;
- an inner pipe provided within the silencer body; and
- a noise absorbing pipe in communication with an exhaust pipe of a fuel cell and housed within in the silencer body,
- wherein the inner pipe and the noise absorbing pipe create first and second flowing paths of exhaust gas inside the silencer body,
- wherein the noise absorbing pipe is provided with a noise absorbing material on a periphery thereof,
- wherein the noise absorbing material is a conductive material grounded to a vehicle body via the silencer body, and
- wherein the silencer and the vehicle body are fixed by a conductive fixing jig,
- wherein the silencer body comprises a cylindrical shell having a pair of end walls provided at both openings thereof, each of said pair of end walls has a dual-plate structure,
- wherein a first portion of the noise absorbing material is provided between the dual plates of each of said pair of end walls, and
- wherein a plurality of transmitting holes is formed through a portion of said at least one of the pair of end walls facing the inner pipe.
14. The silencer for a fuel cell vehicle according to claim 13, wherein the noise absorbing pipe has a plurality of through-holes on a pipe wall thereof.
15. The silencer for a fuel cell vehicle according to claim 14, wherein the pipe wall is provided with a pair of slits, and
- a portion of the pipe wall placed between the pair of slits is outwardly bent into a curved shape so as to serve the pair of slits as the through-hole.
16. The silencer for a fuel cell vehicle according to claim 13, wherein the silencer further comprises:
- a first separator arranged parallel to the end walls within the silencer body;
- a second separator arranged parallel to the end walls within the silencer body;
- a first muffling chamber formed between one of the end walls and the first separator;
- a second muffling chamber formed between the first separator and the second separator, wherein a second portion of the noise absorbing material is provided inside the second muffling chamber; and
- a third muffling chamber formed between the second separator and the other end wall.
17. The silencer for a fuel cell vehicle according to claim 16, further comprising an exhaust flow-out pipe in communication with an outside of the silencer,
- wherein the exhaust gas flows along the first flowing path by passing through the noise absorbing pipe, the third muffling chamber, the inner pipe, the first muffling chamber and the exhaust flow-out pipe.
18. The silencer for a fuel cell vehicle according to claim 16, further comprising an exhaust flow-out pipe in communication with an outside of the silencer,
- wherein the noise absorbing pipe has a plurality of through-holes formed on a wall thereof;
- wherein the inner pipe has a plurality of through-holes formed on a wall thereof; and
- wherein the exhaust gas flows along the second flowing path by passing through the noise absorbing pipe, the plurality of through-holes of the noise absorbing pipe, the second muffling chamber, the plurality of through-holes of the inner pipe, the inner pipe, the first muffling chamber and the exhaust flow-out pipe.
19. The silencer for a fuel cell vehicle according to claim 18, wherein the exhaust gas also flows along the first flowing path by passing through the noise absorbing pipe, the third muffling chamber, the inner pipe, the first muffling chamber and the exhaust flow-out pipe.
20. The silencer for a fuel cell vehicle according to claim 13, wherein the noise absorbing material includes stainless steel.
21. The silencer for a fuel cell vehicle according to claim 13, wherein the noise absorbing material includes carbon.
22. The silencer for a fuel cell vehicle according to claim 13, wherein the noise absorbing material includes at least one of nylon and polyester.
23. The silencer for a fuel cell vehicle according to claim 13, wherein the plurality of transmitting holes faces the noise absorbing pipe.
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Type: Grant
Filed: Nov 30, 2005
Date of Patent: Apr 13, 2010
Patent Publication Number: 20060113145
Assignee: Honda Motor Co., Ltd. (Tokyo)
Inventors: Tsutomu Toyoshima (Saitama), Hiroshi Saito (Saitama), Haruki Imamura (Saitama)
Primary Examiner: Jeffrey Donels
Assistant Examiner: Forrest M Phillips
Attorney: Lahive & Cockfield, LLP
Application Number: 11/292,054
International Classification: F01N 1/08 (20060101);